The present invention generally relates to a xeropraphic reproduction machine and, more particularly, to a toner dispensing cartridge for such a machine.
In xerographic type reproduction machines, latent electrostatic images of a document being copied or printed are generated on a charged surface of a moving recording member, such as a drum or belt photoreceptor, through exposure of the document being copied or in accordance with an electronic image signal input. Following exposure, the latent electrostatic images on the recording member are developed at a developing station, which, in typical present day practice, comprises one or more magnetic brushes for bringing a developer, usually a mixture of carrier beads and toner, into developing relation with the recording member and the image thereon. Following this, the developed image is transferred at a transfer station to a copy substrate material such as a sheet of paper. After transfer, the copy substrate material is fixed, as by fusing, to provide a permanent plot or reproduction.
In the course of developing images as described above, the toner portion of the developer mixture is depleted and, to maintain the necessary proportion of toner to carrier, fresh toner must be added from time to time.
Various types of toner re-supply systems are known in the prior art, as for example, the canister or cartridge type disclosed in U.S. Pat. No. 3,337,072 (DelVecchio et al.). In Del Vecchio, a toner supply canister consisting of relatively rotatable inner and outer concentric tubes, each with a toner dispensing opening, are used. The supply of fresh toner is held in the inner tube, and by rotating the inner tube relative to the outer tube, the toner dispensing openings in each are brought in alignment. Another system is shown in U.S. Pat. No. 3,339,807 (Eichorn). There, the toner supply canister, once mounted, rotates to bring the toner dispensing holes opposite a series of openings in a stationary grid. Preparatory to this, a tear away strip, which seals the holes during shipment, is first removed. In another prior art system shown by U.S. Pat. No. 4,089,601 (Navone), a toner canister housing is installed in the machine following which the canister is turned to communicate the toner dispensing openings within a developer sump. In U.S. Pat. No. 4,688,926 (Manno), a rotatable toner supply cartridge has a row of toner discharge ports with a toner rejecting rod with flats opposite each port. The rod, or in another embodiment, a slide plate, is periodically rotated coincident with cartridge rotation to provide a dispensing of a controlled amount of toner into a developer housing beneath the dispenser.
A common requirement for a gravity feed type of toner dispensing system is that toner be deposited as close to the vertical, or six o'clock position, as possible. This is to ensure that the toner be deposited directly into the developer mixture located below the toner cartridge, generally in a sump type arrangement. If any toner exits the toner dispenser in an area outside of, for example, the 4 to 8 o'clock angular range, the toner is apt to settle onto the surface of the developer housing where it may become airborne and enter as a contaminant into other parts of the machine. This type of unwanted toner dispensing may occur, for example, by small amounts of toner which are on the edges of the dispensing ports not falling free of the cartridge until the cartridge rotates past the preferred disposal area. According to one aspect of the present invention, a flexible flap member is longitudinally positioned adjacent to, and extending, over the toner dispensing ports in the toner cartridge and is mounted so as to be generally tangentially attached to the exterior surface of the cartridge. More particularly, the invention is directed toward a toner cartridge comprising: a tube-like cylinder adapted to contain a supply of toner, said cylinder having a plurality of toner discharge ports therein for the discharge of toner from said cylinder, said toner discharge ports extending at least partially along the longitudinal surface of said cylinder, and a flexible flap member attached to the exterior of said cylinder and adjacent said discharge ports so as to overlie said ports.